Determine via a three year case control study whether dietary components particularly fats and (low) cellulose may serve as risk factors in the etiology of breast cancer. Utilize a validated questionnaire to elicit the dietary information which will include differential anthropometric measurements. Study a population which will be composed of 500 newly diagnosed breast cancer cases of which 300 will be European and American born and 200 will be Asian-African born and include one thousand controls. Match controls to patients on age, parity, menarche, country of origin, period of immigration to Israel, etc. Collect pathology slides for possible future studies. Perform analysis separately for the two main ethnic groups as well as for pre- and postmenopausal women.